Most people have been on a baseball diamond and a basketball court. At least once in their life, they’ve walked across a football field. But relatively few people have ever set foot inside a boxing ring.

Unlike most sports playing fields, a boxing ring is a temporary structure. Four people can assemble a ring in less than three hours, although promoters complain that workers being paid by the hour often take longer.

The basic components of a boxing ring are the same whether the site is Madison Square Garden, a glitzy Las Vegas hotel-casino, or a small union hall in Pennsylvania. Plywood boards roughly five feet long and three feet wide are set atop a skeletal steel frame. Foam padding an inch to 1 1/2 inches thick is placed on top of the boards. Then a large piece of canvas is stretched over the padding.

Most sports have variations in playing conditions. Artificial turf versus natural grass is a universal divide. Baseball fields have varying dimensions beyond the infield. There are dead spots on the parquet floor at the Fleet Center in Boston and patches of soft ice in many hockey arenas. There’s more variation in boxing rings than meets the eye.

First, there’s the matter of size. Most professional rings are between 18 and 22 feet squared inside the ropes. Punchers prefer a small ring. Stylists would rather do battle in a large one. The “speed” of a boxing ring depends on the thickness of the foam padding, the tightness with which the plywood boards are wedged together, and how tautly the canvas is stretched. The “faster” the ring, the better it is for movement. A slow ring negates speed, much like heavily watering the base paths in baseball cuts down on stealing. But the firmer (and faster) the canvas, the more likely it is that a fighter will be hurt if he’s knocked down and his head slams against the canvas.

The canvas isn’t a uniformly hard surface. It has a spongy feel that takes a while in the gym to get used to. Moving on it is more like walking on a gym mat than on a regular floor.

In theory, the promoter is responsible for setting up the ring, and the state athletic commission overseeing a fight is responsible for ensuring that minimum safety standards are met. But that leaves room for gamesmanship. Thus, ring size is sometimes specified in contracts for major fights, although a few venues (like Madison Square Garden) have their own ring, which means that size is predetermined. As for other variables, the commission is supposed to ensure a level playing field that doesn’t give an advantage to either fighter.

A boxing ring looks different from the inside, particularly when it’s shared with another man who is intent upon rendering you unconscious. There’s no place to hide. Once a fighter climbs the stairs, he’s roped in, unable to leave until his night’s work is done. The outer reaches of the arena fade into darkness, but the fighters can hear the roar of partisans screaming for blood.

Ancient Rome, the Colosseum. “Morituri te salutamus … We who are about to die salute you.”

The fighter blots out the crowd and focuses on his opponent. He is standing on Muhammad Ali’s dance floor, Mike Tyson’s killing field.

When a fight ends, the multitude pours into the ring. Often, the ring canvas, which was clean at the start of the evening, resembles a Jackson Pollack painting fashioned from mucous and blood. The promoter, each fighter’s camp, and hangers-on jostle for position to be seen on television and stand at the victor’s side. The boxing ring, which moments before was the site of glory and pain, no longer seems like hallowed ground.

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Many insiders consider super-middleweight Jaidon Codrington (8-0, 8 KOs) to be the best young prospect in New York. Boxing fans can make their own judgment when Codrington takes on Levan Easley (17-11, 8 KOs) at the Manhattan Center tonight. Light-heavyweight Curtis Stevens (7-0, 6 KOs) and junior-welterweight Emmanuel Clottey (22-6,14 KOs) are among the other fighters slated to see action.

The Manhattan Center is located at 311 West 34th Street. Doors open at 6 p.m. The first fight is scheduled for 7 p.m. Tickets are priced at $150, $100, $75, $50, and $35, and can be purchased at the door or in advance by calling 212-947-2577. Seven bouts are scheduled.